Tool holder with built-in cavities

ABSTRACT

A tool holder having a main body for coupling the tool holder to the spindle of a machine tool and having a clamping surface connected thereto for clamping a tool, characterized in that the tool holder has at least one portion shaped in one piece by primary shaping, which in its interior has one or more cavities that form an enclave in the portion shaped by primary shaping.

FIELD OF THE INVENTION

The invention relates to a tool holder for a tool, in particular in theform of a drill, milling cutter or friction tool or cutter head, that isrotatable about an axis of rotation.

BACKGROUND OF THE INVENTION

It is known for the shaft of such a tool to be held in a centralreceiving opening of an annular, self-contained part, most oftenembodied as a tube part, of a tool holder by means of a press fit. Thistube part forms the end toward the tool of a tool holder of otherwiseconventional design.

This tube part of the tool holder can be widened by heating so far inthe radial direction that the cold shaft of the tool can be thrust intothe tube part or pulled out of it. As soon as the tube part has cooleddown again, a pressure bond between it and the shaft of the tool, bymeans of which pressure bond the tool is reliably fixed in the toolholder (shrink-fit technology; see for example EP 1 353 768 B1).

Alternatively, chucking can also be done hydraulically. For thatpurpose, inside the aforementioned tube part of the tool holder, ahydraulic clamping device is provided, which upon imposition ofhydraulic pressure reduces its inside diameter embracing the tool shaftand thus chucks the tool shaft by frictional engagement.

So-called collet chucks are a further alternative; in them, the toolshaft is kept clamped by frictional engagement with the aid of a collet,by driving the collet, which is provided with an outer cone, into acomplementary conical seat and thereby causing it to close.

It is also known for tools in the form of so-called cutter heads to beconnected by positive engagement, with the aid of a usually central setscrew and one or preferably more drivers to the tool holder, which hereis usually called a cutter head receptacle.

Collet chucks of the type described have proved themselves very well inpractice.

In general in collet chucks of the described type, there is the problemthat under unfavorable circumstances, because of reaction forces thatoriginate at the cutting edges of the tool, vibration is induced, whichnot infrequently is in or near the resonant range. Such vibration arisesbecause the tool cutting edges are exposed to rapidly alternatingstresses, for instance because in rapid succession, n and n+1 cuttingedges mesh with one another in alternation. This vibration can makeitself felt so markedly in the complete system comprising the tool,collet chuck and machine tool, that the cutting speed, for instance,and/or other cutting parameters have to be reduced, which impairs theperformance of the concrete system and is therefore unwanted.

It is known that the tendency to vibration of such a complete system canbe favorably affected in some cases by “softer” chucking of the tool.

It is the object of the present invention to disclose a means whichmakes chucking the tool in a way that especially favorably affects thevibration behavior of the tool, without making compromises in themachining precision.

SUMMARY OF THE INVENTION

This object is attained by a tool holder for chucking a tool. The toolholder has a main body for coupling the tool holder to the spindle of amachine tool and a clamping portion, preferably connected to it insingle-substance fashion or at least in one piece, for clamping a toolshaft or a cutter head. In practice, the clamping portion is oftenembodied as a tube part, which in turn is embodied such that the toolshaft can be fixed thermally or hydraulically in the tube part. Ideally,such a tube part is embodied such that the tool shaft can beshrink-fitted into the tool receptacle furnished by it; that is, thetool receptacle, which in the cold state is undersized compared to theouter diameter of the tool shaft, can be widened so far by theapplication of heat that the cold tool shaft can be inserted and is heldin a manner fixed against relative rotation, at least predominantly, bythe press fit ensuing as the tube part cools down again.

Regardless of how the clamping portion is embodied, it is providedaccording to the invention that a tool holder has at least one portionshaped in one piece by primary shaping, which has one or more cavitiesthat are located entirely in the interior of that portion and that forman enclave in the portion shaped by primary shaping. The term “enclave”is understood to mean a structure that is completely self-containedrelative to its surroundings and in particular toward the outside. Alid, stopper or the like screwed on or in or fixed by welding is notneeded.

Surprisingly, it has been found that a cavity that is embodied ascompletely self-contained and completely inside a portion shaped byprimary shaping has excellent damping properties. This positive effectis multiplied if a plurality of cavities is provided.

Moreover, the cavities embodied according to the invention offer thepossibility of so-called “constructive balancing”, thus eliminating thenecessity of touching the surface of the tool holder in order to makeone or more bores have in the surface of the tool holder for the sake ofbalancing. This is because such bores often interfere with the handlingand use of the tool. Precisely in tool holders in the form of shrink-fitcollets, such ores are often problematic because cooing lubricant and/orcoolant fluid can accumulate in them and are not easily blown out of thebore if the tool holder, after being shrink-fitted on or after theshrink fit is undone, is to be showered with water for the sake of rapidcooling and then blown dry extremely quickly with a focused stream ofair.

It must be noted that voids, microscopic pores or other flaws that occurat random and undefined places in the microstructure of the material arenot cavities in the sense of the invention. Preferably, in the sense ofthe invention a cavity is exclusively a construction that has a definedgeometric form embodied in accordance with a rule determined in advanceand ideally has a radial length and a length in the direction of theaxis of rotation of the tool holder that is greater than 1/10 of amillimeter and preferably even greater than 1 mm. It is especiallypreferable to lend the same design to a plurality of cavities, asidefrom unavoidable production tolerances.

According to the invention, it is provided that a plurality of cavitiesare located such that they are located on at least two, and even betterthree, coaxial imaginary cylindrical or conical jackets one inside theother.

Within the context of an advantageous further development, it isprovided that the cavities in the circumferential direction each form anannular-portion-like channel, which preferably extends concentrically tothe axis of rotation of the tool holder entirely in the interior of theportion. Ideally, the cavities each form an annular channel, which iscompletely self-contained in the circumferential direction.

A further development alternative provides that that the tool holder hasa plurality of cavities, which extend substantially in the directionparallel to the axis of rotation or along a helical line that windsaround the axis of rotation and which are located preferablysymmetrically to one another in the circumferential direction. Suchstructures also have a good damping characteristic and have additionallyproved to be especially effective means for preventing so much heat tobe fed to the tool shaft prematurely from the tube part that theshrinking out or undoing the shrink fit is made more difficult.

The cavities, in a plane perpendicular to the axis of rotation or in aplane that completely contains the axis of rotation, should have a roundcross section or a flat cross section. A flat cross section isunderstood to be a substantially rectangular cross section, whose lengthin the radial direction is less than in the circumferential directionand in the direction of the axis of rotation R. Preferably, such a flatcross section comprises two lateral arcs concave toward the interior ofthe cavity and two straight lines, joining the arcs.

A hexagonal cross section is optimal, especially where the cavities arelocated so close together that the partitions between adjacent cavitiesform a honeycomb structure.

Expediently, the tool holder has more than 10 and preferably more than15 and ideally more than 25 cavities, each forming an enclave, that areindependent of one another and that are all preferably embodied entirelyin the portion that forms the clamping surface, which is ideallyembodied as a tubular portion. As a result, compared to thecorresponding solid material, a reduction in weight can be attained,which makes the manipulation of the tool holder perceptibly easier.Because of the reduction in the inertial mass of the tool holder, thismakes itself felt in a positive way not least upon an automatic toolchange, without having to accept sacrifices in strength that are a majorconsideration. Ideally, so many cavities, with such large dimensions,are provided that the mass of the tool holder, not yet equipped with atool, is reduced by at least 10% and even better by at least15%—compared with an identically designed tool holder of solid material.Moreover, such an embodiment also leads to a savings of material, whichnot least in mass production of such tool holders already adds up in ashort time and makes itself positively felt.

It is especially favorable if the cavities form a three-dimensional setof cavities, which is distinguished in that progressively in the radialdirection from the inside outward, a plurality of cavities are locatedone after another, preferably in alignment with one another, and at thesame time a plurality of cavities are located one after another in thedirection of the axis of rotation R, and preferably are in alignmentwith one another. Optimally, respective adjacent cavities are located soclose together that in a plane perpendicular to the axis of rotationthey form a total cross section, whose total area is occupied by amaximum of 60%, and even better a maximum of 40%, of the sum of thecross-sectional area of the lands.

The embodiment possibilities just described lead to a set of cavities,which forms a “honeycomb structure” or “porous structure that isbionically oriented on the principle of large mammal bones: There is nodiscontinuity in strength, if a hollow bearing structure does not havecontinuously massive walls but instead is embodied as porous in thevicinity of the center of each wall. This porous structure has anexcellent damping action.

Another preferred embodiment provides that at least one but preferably aplurality of cavities are embodied in the main body, in fact in a regionlocated outside the clamping surface or the tube part. Ideally, this atleast one cavity is positioned such that in the radially inwarddirection it is located entirely in a region which is embraced on itsouter circumference by the retaining flange for the handling system, forautomatic manipulation of the tool holder. In this region, which istypically the most massive part of a tool holder, cavities have untilnow never been provided for damping purposes. The inventor has made thesurprising finding, counter to previous suspicions, that making cavitiesin this quite massive region certainly does not remain withoutperceptible effect, but instead a markedly perceptible effect isexhibited, yet without excessively reducing the strength.

Preferably, this at least one cavity in the main body is designed as anannular disk, whose axis of symmetry coincides with the axis of rotationR and whose length in the direction parallel to the axis of rotation issubstantially less, preferably by at least a factor of 3, than itslength in the radial direction perpendicular to the axis of rotation R.

Alternatively, the at least one cavity can have the form of acylindrical ring, whose wall thickness in the radial directionperpendicular the axis of rotation R is substantially less, andpreferably at least by a factor of 3, than its length in the directionparallel to the axis of rotation R. A cavity so embodied also exhibits astill sufficiently pronounced effect.

Expediently, a plurality of cavities are located in the direction alongthe axis of rotation R, or in the direction along a straight lineinclined by up to 10° relative to the axis of rotation R, in alignmentwith one another. As a these cavities come to be located on an imaginarycylindrical or conical jacket. It is especially favorable if a pluralityof cavities are located such that they are located on at least two, andeven better three, imaginary cylindrical or conical jackets locatedcoaxially one inside the other and the channels located on differentcylindrical or conical jackets are not aligned in the radial directionbut instead are preferably located with a center offset relative to oneanother.

This kind of regular arrangement and the aforementioned furtherprovisions have a favorable effect on the vibration behavior.

The invention moreover addresses the problem of how the damping and/orclamping behavior of a tool holder can be varied hydraulically in themost reliable way.

In the prior art, it is known that the damping and/or clamping behaviorof a tool holder can be varied by providing at least one cavity in thetool holder, which cavity is put more or less strongly under hydraulicpressure as needed. The previously known constructions typically operateeither with individual bores, made retroactively from outside into thetool holder, or with cavities inside the tool holder, which are eitherformed by regions that are sealed off from the outside by a lid or atube thrust into the tool holder, or are formed by forming the toolholder of two portions that are welded together and as a result betweenthem form the cavity or cavities.

These cavities produced in multiple parts require careful sealing. Theeffort and expense for sealing increases sharply especially whereverwork is to be done with high hydraulic internal pressure, in order tobrace the tool holder with great force intrinsically. Not least,cavities produced in multiple parts by the use of lid inserts or bushesare increasingly threatened with leakage as the pressure rises. Inparticular, gradual leakage in operation that goes unnoticed at first isextremely unwanted, since the prestressing of the tool holder thatchanges gradually is usually not noticed until the machining qualityattainable with it has dropped significantly.

It is the object of the invention to provide an improvement here.

For attaining this object, a tool holder for chucking of a tool shaft byfrictional engagement, having a main body for coupling the tool holderto the spindle of a machine tool and having a clamping surface, joinedto it, or a tube part joined to it, for fixation or shrink fitting of atool shaft is proposed, which is distinguished in the tool holder has atleast one portion shaped in one piece by primary shaping, in which anouter connecting channel, preferably beginning at the outercircumference, is embodied that extends into the interior of the portionand there widens, forming at least one cavity; this cavity is locatedentirely in the interior of the portion—that is, an adjacent portion,such as a lid, bush, or a main body welded to the tube part, is notinvolved in the formation of the cavity. The term “widening” in thesense of the invention can be used, as soon as the inside cross sectionof the outer connecting channel (viewed along its primary flowdirection) is less than the sum of the inside cross section or sectionsof the cavity or cavities communicating with it.

In the affected portion, a relatively large cavity is accordinglyembodied, which can be put under hydraulic pressure from outside via asmall opening, with the aid of a pressure transducer, in the desiredmanner. The cavity or cavities are tight on their own, even at the mostextremely high internal pressures, since they are embodied entirelyinside the applicable one-piece portion. Only the outer connecting lineor outer connecting lines require careful sealing. This can be reliablyaccomplished without major effort or expense.

Preferably, the at least one cavity is filled with a fluid, and apressure transducer, preferably to be actuated from outside, is builtinto the at least one outer connecting channel, by means of whichtransducer the fluid can be subjected to pressure.

It is especially favorable, if here as well the cavities form athree-dimensional set of cavities, which is distinguished in thatprogressively in the radial direction from the inside outward, aplurality of cavities are located one after another, preferably inalignment with one another, and at the same time, in the direction ofthe axis of rotation R, a plurality of cavities are located one afteranother, and preferably in alignment with one another. Via a set ofcavities of this kind, a precisely metered and spatially desirablydefined, distributed pressure action can be generated over a wider area.

Optimally, at least 10 and even better at least 20 such cavities arepresent, which are preferably all located in the interior of theone-piece tube part. The cavities expediently communicate with oneanother via internal connecting channels. At least one cavitycommunicates directly, via at least one outer connecting channel, with apressure transducer, so that via the pressure transducer, the pressureof the fluid with which the cavities are filled can be specified inadvance.

The invention also addresses the question of how coolant or coolinglubricant is fed from the coupling side of the tool holder to its endtoward the tool in a simplified way, in order to enable optimallycooling or lubricating the area in which the tool is in engagement withthe workpiece.

In the prior art, it is known for this purpose to make a plurality ofbores, intersecting one another, into the wall of the tool holder inorder in this way to create a continuous fluid line from the area of thecoupling of the tool holder to its end toward the tool. In so doing, atleast one substantially radially extending bore must be made, whichmeets a bore extending substantially in the direction of the axis ofrotation. This radially extending bore, where it intersects the outercircumferential surface of the tool holder, must be closed. This takeseffort and expense to accomplish. Moreover, such a closure represents anaccumulation of mass, which increases the imbalance that has to bebalanced again then.

This object is attained by a tool holder which has at least one coolantsupply line that and extends from the side of the tool holder toward thetool that is to be chucked into the main body and preferably dischargesinto the inner chamber bounded thereby. The coolant supply line changesits directional course at least one location, without having a side armformed by a bore made into the tool holder from the outer surface of thetool holder. As a rule, at least the portion of the tool holder in whichthe coolant supply line extends is constructed from a metal layermaterial.

Expediently, the coolant supply line has at least one portion thatextends substantially in the radial direction.

The invention also addresses the question of how in tool collet chucksin the form of shrink-fit chucks the undoing the shrink fit can bebetter improved and has therefore set as its object making a shrink-fitchuck available that makes even better undoing the shrink fit possiblethan the shrink-fit chucks known before.

This object is attained by a tool holder having a main body for couplingthe tool holder to the spindle of a machine tool and a tube part, joinedto it, for thermal or hydraulic clamping of a tool shaft, which isdistinguished in that the outer circumference of the tube part has aninduction portion, which comprises a metal that is electrically andmagnetically conductive; moreover, the tube part has a portion, locatedinside the induction portion, that comprises a metal with a highercoefficient of thermal expansion than the metal comprising the inductionportion and both the induction portion and the portion of the tube partlocated inside the induction portion are an integral, one-piececomponent circumferential wall of the tube part.

The invention furthermore addresses the problem of how complexstructures, in particular those that are only poorly accessible fromoutside and/or are undercut, of a tool holder can be manufactured.Complex structures can be manufactured using a so-called layer-meltingprocess, in which the structure to be generated is produced by weldingor sintering metal material onto it point by point or layer by layer.

By its nature, however, a layer-melting process progresses only slowlyin production and is therefore intrinsically not predestined formass-producing objects with a relatively large metal mass.

It is therefore a further object of the invention to disclose a toolholder which, despite its complex structures, can be manufactured morerationally than before.

This object is attained with a tool holder (which is preferably embodiedfor clamping of a tool shaft at least predominantly by frictionalengagement) that has a main body for coupling the tool holder to thespindle of a machine tool and also has a clamping portion joined to it,which is preferably embodied as a tube part for shrink fitting insertionof a tool shaft. A first portion of the tool holder comprises forged,rolled or cast metal, which as a rule indicates a correspondingmicrostructure of this first portion. A second portion of the toolholder comprises a metal layer material. The term “metal layer material”here designates a material that comprises individual metal layers, zonesor points that have been successively melted onto one another or weldedor sintered to one another. This is often done with the aid of a laser.This type of primary shaping, too, as a rule leaves a characteristicmicrostructure behind, so that the type of production of the tool holderin this case is expressed in a physical property.

It should be noted that the term “metal layer material” in each casedescribes a material that in not-insignificant proportions andpreferably predominantly—relative to its mass—comprises metal. The metallayer material can comprise exclusively metal layers, zones or points,even without other kinds of components, or at least without other kindsof components that go beyond the category of contaminants. It can beexpedient to mix in different metals and/or alloys thereof. Forinstance, the use or addition of at least one shape memory alloy (FGL)has proved expedient. Optionally, however, the metal layer material canalso be made from at least one metal starting material or one metalpowder, which contains components, affecting the material properties, ofat least one nonmetal material. The addition or admixture of a ceramicmaterial and/or of at least one carbon compound and/or of at least oneplastic or at least one bonded fiber material formed with theinvolvement of the plastic can be considered here.

Such additions of material can be done throughout or only locally.

The major advantage of this type of manufacture is that the particularportion (as a rule, the main body), which can be machined much morerationally in the conventional way, continues to be so machined. Theslower layer-melting process is used only for the spatially limitedsecond portion, in or on which the complex structures are embodied,which conventionally are difficult if not impossible to manufacture.This makes the production process multiple times faster, without havingto dispense with embodying complex structures.

This object is furthermore attained by a method as recited in thecoordinate method claim. Within the scope of this method it is providedthat a tool holder having a main body for coupling the tool to thespindle of a machine tool and having a clamping surface, preferably inthe form of a tube portion, joined to it for fixation and in particularfor shrink fitting of a tool shaft is produced such that a firstportion, preferably the main body, is produced as a rotary part from thesolid or from a pre-forged or precast blank, preferably of tool steel,and a second portion, preferably the tube part, is constructed ofindividual metal layers that are generated successively on one another,until the clamping surface has a predetermined shape. It should also benoted that the second portion may possibly be only a local area of thetool holder, for instance an undercut area to be embodied only locally,which is recessed from the tool holder, conventionally made bymetal-cutting machining, and is then introduced afterward with the aidof a layer-melting method, in order to complete the tool holder.

Preferably, the method is carried out such that the metal layers formingthe second portion are melted from a mixture of different or differentlyalloyed metals. In this way, certain areas of the second portion can bemade especially useful in terms of material for certain tasks. Forinstance, places that are particularly locally stressed can be made froma material with increased resistance, without having to make the entiresecond portion at the same time from this kind of material, which is notinfrequently expensive, and putting it into the desired form might befeasible only by expending more time. The same is true for places wherefor instance especially high electrical and/or magnetic conductivity isexpected. For example, the clamping portion embodied as the tube partcan be given an outer portion which comprises a metal material in which,under the influence of a magnetic alternating field, heat can begenerated inductively, and it can contain an inner portion, joined in asingle material with it and embodying the tool receptacle, thatcomprises a metal material which has higher thermal expansion than thematerial of the outer portion.

Quintessentially, the composition of the metal layers is locally variedmore than merely insignificantly, in such a way that locally, the metallayers have special mechanical and/or electrical and/or magneticproperties.

Preferably, the production method of the invention is carried out suchthat the aforementioned second portion, after the conclusion of themelting onto one another or welding to one another of the individuallayers, is subjected to a heat treatment. Preferably, this heattreatment brings about a change in microstructure and/or ideally ensuresthat the intrinsic stresses in the first portion are diminished.

The method of the invention can be performed especially efficiently ifthe first portion of the tool holder, which comprises forged or castmetal, is used as a substrate, onto which the second portion of the toolholder, which comprises a metal layer material, is gradually applied. Inthis way, especially high positional accuracy of the first and secondportions relative to one another can be ensured, which has a favorableeffect on the most precise possible concentricity, which a tool holderof this kind should have. Moreover, a separate connection operation andthe precise alignment of the portions relative to one another requiredin the course of the connection operation become unnecessary.

For other instances of use (namely those in which the second portion isto be subjected to an especially expensive heat treatment), it hasproved favorable for the first portion or the tube part first to beconnected to the main body after the conclusion of the heat treatment,so that the heat treatment of one part of the microstructure does notaffect the other part. Logically, the same applies if the main body, forinstance, is subjected to case hardening. The aforementioned connectionis preferably made by welding, and in particular by means of a frictionwelding operation.

The second portion or the tube part, after the conclusion of the meltingonto one another or welding to one another of the individual layers andpreferably after the ensuing heat treatment, is subjected to rotarymachining and/or external circular polishing. In the process, such amachining ideally takes place only after the main body is connected tothe tube part, since in this way precise concentricity of the toolholder can be achieved most simply.

On a case by case basis, it may be expedient that the portion shaped inone piece by primary shaping comprises solely metal layers, zones orpoints, entirely without other components or at least without othercomponents that extend beyond the category of contaminants.

On the other hand, the portion shaped in one piece by primary shapingcan be produced from at least one metal starting material or a metalpowder, which includes components of at least one nonmetal material thataffect the tool properties.

Further embodiment possibilities, effects and advantages can be learnedfrom the ensuing description of some concrete exemplary embodiments inconjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The description will be made in conjunction with the drawing figureslisted below.

FIG. 1 shows a first exemplary embodiment of the invention in a sectionalong the axis of rotation R.

FIG. 2 shows the same section as FIG. 1, in a perspective view.

FIG. 3 shows a second exemplary embodiment of the invention in a sectionalong the axis of rotation R.

FIG. 4 shows the same section as FIG. 3, in a perspective view.

FIG. 5 shows a view from the front, in a section taken along the lineA-A.

FIG. 6 shows an enlarged detail of a cavity of FIG. 3.

FIG. 7 shows a third exemplary embodiment of the invention in a sectionalong the axis of rotation R, that is, in a section taken along the lineB-B.

FIG. 8 shows a perspective view of the third exemplary embodiment, in asection along the line Y-Y.

FIG. 9 shows a view from the front, also in a section along the lineY-Y.

FIG. 10 again shows a sectional view of the third exemplary embodiment,in a section along the line C-C.

FIG. 11 shows a fourth exemplary embodiment of the invention in asection along the axis of rotation R.

FIG. 12 shows a perspective view of the fourth exemplary embodiment, ina section along the line D-D.

FIG. 13 shows a view from the front, again in a section along the lineD-D.

FIG. 14 again shows a sectional view of the fourth exemplary embodiment,in a section along the line E-E.

FIG. 15 shows a fifth exemplary embodiment of the invention in a sectionalong the axis of rotation R.

FIG. 16 shows a view from the front, in a section along the line F-F.

FIG. 17 shows a perspective view of the fifth exemplary embodiment,which is cut away.

FIG. 17a shows the area marked X in FIG. 17 on a larger scale.

FIG. 18 again shows the fifth exemplary embodiment, in a section alongthe axis of rotation R but at a different section angle.

FIG. 19 shows a sixth exemplary embodiment of the invention in a sectionalong the axis of rotation R.

FIG. 20 shows a view from the front, in a section along the line G-G.

FIG. 21 shows a perspective view of the sixth exemplary embodiment,which is cut away.

FIG. 21a shows the area marked X in FIG. 21 on a larger scale.

FIG. 22 again shows the sixth exemplary embodiment, in a section alongthe axis of rotation R but at a different section angle.

FIG. 22a shows a perspective view of the seventh exemplary embodiment,which is cut away.

FIG. 22b shows the area marked X in FIG. 22a on a larger scale.

FIG. 23 shows an eighth exemplary embodiment of the invention in asection along the axis of rotation R.

FIG. 24 shows a perspective view of the eighth exemplary embodiment,which is cut away.

FIG. 24a shows the area marked X in FIG. 24 on a larger scale.

FIG. 25 shows a ninth exemplary embodiment, which is closely related tothe eighth exemplary embodiment.

FIG. 25a shows a tenth exemplary embodiment of the invention in asection along the axis of rotation R.

FIG. 25b shows a perspective view of the tenth exemplary embodiment,which is cut away.

FIG. 25c shows the area marked X in FIG. 25b on a larger scale.

FIG. 26 shows an eleventh exemplary embodiment of the invention in asection along the axis of rotation R.

FIG. 27 shows a view from the front, in a section along the line H-H.

FIG. 28 shows a perspective view of the eleventh exemplary embodiment,which is cut away.

FIG. 28a shows the area marked X in FIG. 28 on a larger scale.

FIG. 29 shows a twelfth exemplary embodiment in a section along the axisof rotation R.

FIG. 30 shows a thick-walled shrink-fit chuck from the prior art andserves to illustrate the problems to be encountered in the prior art.

FIG. 31 shows a thirteenth exemplary embodiment in a section along theaxis of rotation R.

FIG. 32 shows a fourteenth exemplary embodiment in a section along theaxis of rotation R.

FIG. 33 shows an enlarged cutout of the area of the tube part and thecap nut, which is marked in FIG. 32 by a circle.

FIG. 34 shows an enlarged cutout of the area below the retaining flangeof the handling system, which is marked in FIG. 32 by a circle.

FIG. 35 shows a perspective view that corresponds to FIG. 32.

FIG. 36 shows a fifteenth exemplary embodiment in a section along theaxis of rotation R.

FIG. 37 shows an enlarged area of the cutter head, which is marked inFIG. 36 by a circle.

FIG. 38 shows a perspective view, which corresponds to FIG. 36.

FIG. 39 shows an enlarged view of the area that is marked with a circlein FIG. 38.

FIG. 40 shows a section perpendicular to the axis of rotation throughthe cutter head and the clamping portion on which the cutter head isseated.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The first exemplary embodiment will now be described in conjunction withFIGS. 1 and 2.

This tool collet chuck 1 comprises a main body 2 and a tube part,protruding from it, which in this exemplary embodiment forms theclamping portion 3 (in the corresponding exemplary embodimentshereinafter, this will be called “the tube part 3” for short throughout,but what is meant is always “the clamping portion 3 embodied in the formof a tube part”). A tool receptacle 4 is embodied in the interior of thetube part 3.

The tool collet chuck is embodied as a so-called shrink-fit chuck, whichis generally preferred. The inside diameter of the tool receptacle 4embodied in the tube part 3 is somewhat smaller than the outsidediameter of the tool shaft, not shown, so that the tube part 3 keeps thetool shaft, not shown, firmly in a press fit as soon as the tube part 3cools down again after the insertion of the tool shaft. As seen quitewell in FIG. 1, the main body 2 has a coupling portion 5. The latterserves to couple the unit comprising the tool collet chuck 1 and thetool held by it to a machine tool. The coupling portion is embodied hereas a hollow shaft coupling (HSK coupling), which is advantageous, butthe protection sought is not limited to this. Instead, protection isalso sought for other kinds of embodiment of the coupling, such as asteep-taper conical coupling shaft.

Furthermore, as a rule, the main body 2 has a retaining flange 6, towhich a handling system of any type can be connected in order to be ableto manipulate the tool collet chuck 1 in an automatic change of tools.

As seen from a glance at FIGS. 1 and 2, the tool holder here is embodiedin multiple parts; that is, it comprises at least two portions shaped byprimary shaping independently of one another, which have been joinedtogether later. In the present case, these are the main body 2 and thetube part 3. The main body 2 is preferably produced conventionally bymetal-cutting machining from the solid or metal-cutting of a pre-forgedblank. It is favorable to produce the main body 2 from a steel that canbe subjected to case hardening.

It is striking that the main body 2 here does not end directly adjoiningits retaining flange 6, but instead changes over on its side toward thetool from the retaining flange 6 with a sudden change in diameter to areduced diameter that can be called an attachment portion 8. Thisattachment portion 8 is from the outset an integral component of themain body 2 and is shaped by primary shaping together with it.Preferably, the attachment portion is designed such that the tube part 3can adjoin it without a change in diameter. The tube part 3 ispreferably produced in one piece by a layer-melting process. Such alayer-melting process is distinguished in that the component is producedlayer by layer; that is—usually with the aid of a laser—a further layerof a metal material, originally in powder form, is melted or sinteredonto every previous layer.

After this, the tube part 3 is preferably subjected to a heat treatment,with the aid of which the desired microstructure of the metal materialis established. Separately from this, the main body 2 is in turnsubjected to a heat treatment and/or case hardening.

As a rule, the procedure is such that the tube part 3 is thereuponjoined to the main body 2. Preferably, the joining is done by welding,ideally so-called friction welding, in which the two components arepressed firmly against one another and in the process rotated relativeto one another, so that the two components, as a result of the heat offriction, heat up so intensely at their contact face K that they finallyfuse together; see FIG. 1.

This is usually followed by further machining, in the context of whichthe tool holder is twisted off at its outer circumference and/orpolished, and the tool receptacle 4 is rubbed or subjected to internalcircular polishing.

Finally, the tool holder is weighted and is then ready for use.

Instead of later fusing together, as has just been described, theprocedure can also be such that the conventionally produced main body 2is used as a substrate, onto which the tube part is applied step by stepor layer by layer. The tube part 3 shaped by primary shaping from onepiece on the specification of what is said above is distinguished inthat in its interior, it has many cavities 9 extending in thecircumferential direction, each of which here forms a self-containedannular channel in the circumferential direction. Each of these cavitiesshown in FIGS. 1 and 2 forms one complete enclave in the tube part 3,and thus does not communicate anywhere with the surroundings of the tubepart or with some other cavity, even locally. In the concrete preferredcase, there are more than 20 cavities. Each of the cavities has alreadybeen formed in the course of the primary shaping of the tube part, andthus has not been machined afterward into the tube part.

As can be readily seen from the drawings, the cavities 9 form a set ofcavities. It is distinguished in that a plurality of cavities arelocated one after another, preferably in alignment with one another, inthe direction of the axis of rotation R. Preferably, a plurality ofcavities are also located one after another progressively in the radialdirection from the inside outward. Ideally, these cavities are also inalignment with one another in the radial direction. Such an arrangementleads to a three-dimensional set of cavities, which from theconstructive standpoint makes a very sensitive adjustment of thechucking characteristic (hardness of the chucking) and of the dampingcharacteristic possible.

A modification, not shown in the drawings, has an appearance such thatindividual cavities of those shown in FIGS. 1 and 2 do not form anenclave but instead communicate with the surroundings of the tube part.

In the sectional planes that completely contain the axis of rotation,the cavities 9 ideally each have a hexagonal cross section, so that in asectional plane in which the axis of rotation R is located, a honeycombstructure ensues; see FIG. 1.

With reference to FIG. 1, it can be noted that the cavities 9 arelocated on three imaginary circular cylinders, each of which isconcentric with the axis of rotation R and has different mean diametersR1, R2 and R3. The cavities 9 each located on an imaginary circularcylinder are in alignment with one another in the direction of the axisof rotation R of the tool holder. Those cavities 9 that are located onthe second imaginary circular cylinder, whose radius R2 is somewhatgreater than the radius R1 of the first imaginary circular cylinder, arenot aligned in the radial direction with the cavities that are locatedon the first imaginary circular cylinder. Instead, they are offset,preferably center-offset. This means that each cavity that is located onthe second imaginary circular cylinder is located (viewed perpendicularto the axis of rotation R) in the interstice between two cavities 9 thatare both located on the first circular cylinder having the radius R1. Ascan be seen from the drawings, this means that the cavities are veryclose together and ideally are located such that cavities located onadjacent circular cylinders overlap in the direction along the axis ofrotation R.

Preferably, those cavities 9 that are located on the third imaginarycircular cylinder, whose radius R3 is greater than the radii R1 and R2,are located in the radial direction in alignment with the cavities 9 ofthe first imaginary circular cylinder.

As can easily be seen from FIGS. 1 and 2, the cavities 9 are eachlocated close together, so that the lands between two adjacent cavitieseach have a length that is less than the maximum cross section of eachof the adjacent cavities.

It has proved especially favorable for adjacent cavities 9 each to belocated so close together that in a plane that completely contains theaxis of rotation R, they form a total cross section whose total area isoccupied by a maximum of 60%, and even better a maximum of 40%, by thesum of the cross-sectional area of the lands. Whether this requirementis met can be ascertained quite simply. Around the set of cavities, animaginary cable line spanning the set of cavities from outside is drawnaround the set of cavities in the cross-sectional plane. The areaencompassed by the cable line is the total cross-sectional area. Some ofthis computational cross-sectional area is formed by the sum of theareas that the lands contribute; the remainder of this area is formed bythe sum of the cross-sectional areas of the individual cavities 9.Preferably, the aforementioned ratio of these areas is maintained.

As a result, the porous structure shown in FIGS. 1 and 2 results, whichhas an excellent damping action and has an influence on how rigidly thetool shaft is chucked. The pores, however, must not reach as far as thesurface of the bearing structure, or at most only a few of them do so;instead, they should actually form enclaves closed on all sides in theinterior of the respective bearing structure.

The damping action of the cavities makes itself optimally perceptibleespecially whenever the cavities, viewed in the direction of the axis ofrotation R, already extend substantially over the entire length, or atleast ⅔ of the length, of the tool receptacle 4 that keeps the toolshaft chucked by press-fitting. It has proved especially favorable ifthe individual cavities are small-celled, in the sense that the crosssection of individual cavity, in the plane that entirely contains theaxis of rotation R, is smaller than 60 mm² and ideally even smaller than30 mm² and in especially favorable cases even smaller than 15 mm².

Surprisingly, such a set of cavities develops an especially advantageousdamping effect particularly whenever the individual cavities 9 have notbeen made retroactively by erosion or drilling, but instead have alreadybeen machined into the tube part 3 in the primary shaping. They thenhave a very precise geometrical shape and a precise location relative toone another—without later interfering with the microstructure of thetube part 3. Precisely those cavities 9 that are embodied as genuineenclaves and have no locally weakening opening with which theycommunicate with the surroundings of the tube part 3 develop anespecially advantageous, strongly damping effect.

As a rule, a set of cavities located in this way simultaneously hasstill another substantial advantage: The set of cavities is located suchthat the heat generated in the outer circumferential surface (skineffect) of the tube part 3 with the aid of an induction coil, not shown,which heat is meant to be used for undoing the shrink fit, or shrinkingout, penetrates only with some delay into the vicinity of the toolshaft. As a result, the time slot within which the tool shaft can bepulled out of the tube part that has been inductively heated and therebywidens becomes longer. This facilitates the shrinking out substantially.

It has proved especially advantageous if, between the inner surface ofthe tool receptacle 4 and the smallest imaginary circular cylinder onwhich cavities are located, there is an unimpeded cylindrical portionthat is continuous in the direction of the axis of rotation, the leastwall thickness W of which amounts to at least 1 mm and preferably atleast 2 mm; see FIG. 1. Moreover, it has proved especially favorable ifthe cavities, on the distal end of the tube part 3, toward the tool, arecovered by a wall that forms an integral component of the tube part andthat has a wall thickness WK of at least 1 mm and preferably at least 2mm. The same logically applies to the wall thickness WU of the wallportion embodied as an integral component of the tube part 3, which wallportion divides the cavities from the outer circumferential surface ofthe tube part. This advantageous form of embodiment applies through allthe exemplary embodiments.

With the aid of the cavities described, still a further effect can beachieved:

Thick-walled shrink-fit chucks for heavy-duty use often have a tendencyto warp upon inductive heating of the tube part for the sake of removingthe tool shaft from the chuck. This sometimes makes the shrinking outmuch more difficult.

This warping is due to the fact that in the inductive heating, first theoutermost circumference of the shrink-fit chuck heats strongly, and theheat inductively generated is transported onward by thermal conductioninto the vicinity of the interior of the shrink-fit chuck only with somedelay. Precisely where the shrink-fit chuck is embodied with thickwalls, the situation then arises at some time or other that theoutermost layer, shown in black in FIG. 30, of the tube part 3 hasalready heated strongly and has also already strongly expanded in thedirection of the axis of rotation R, which is symbolized in FIG. 30 bythe arrow P. At that time, the inner layers of the tube, which aresurrounded by the outermost layer of the tube part, are still cold, andby then they have neither expanded in the radial direction nor in thedirection of the axis of rotation R. As a consequence, the end towardthe tool of the tube part 3 is thrown inward; see FIG. 30. This iscounterproductive, since as a result an additional clamping force isexerted on the tool shaft, which counteracts the tendency of the tubepart 3 to let go of the tool shaft in the course of the heat-causedexpansion of the tool receptacle.

This problem, too, can be overcome by using the cavities 9 of theinvention.

For instance, it is an attractive option to provide a number of cavitiesof the invention (optionally, additional cavities), in the vicinity ofthe wall of the tube part 3 that is located closer to the toolreceptacle than to the outer circumference of the tube part 3.

Precisely how these cavities should be located depends in the finalanalysis also on the individual case and is therefore easy to determinefrom conventional tests for the individual case. As a rule of thumb, itcan be said that the cavities 9 must be located in such a way that theyweaken an inner region of the tube part in the direction parallel to theaxis of rotation R so much that this inner region of the tube part doesnot substantially hinder the expansion of the already-hot outer regionof the tube part in the direction of the axis of rotation R, because thealready-hot outer region of the tube part can impose an expansion in thedirection of the axis of rotation R on the weakened inner region of thetube part, despite the lack of heating there or the only slight heatingthere. A rough impression of how these cavities should approximately belocated for a particular application of this kind is given in FIG. 31.

FIGS. 3 through 5 show a second exemplary embodiment of the invention,which is substantially equivalent to the first exemplary embodiment ofthe invention described in further detail in FIGS. 1 and 2. As a result,what is said for the first exemplary embodiment applies to this secondexemplary embodiment as well, unless differences arise in the ensuingdescriptions of this second exemplary embodiment.

In this second exemplary embodiment, the main body 2 and the tube part 3have been created from the outset in one piece by being jointly shapedby primary shaping. Here, it is the case that the entire tool holder hasbeen constructed by a layer-melting process of the type described above.This takes longer than the above-described production from two separateblanks produced separately from one another by primary shaping, but ithas the advantage that the microstructure is not impeded by welding, andfurthermore a virtually perfect concentricity of the tool holder can beensured even more simply.

The cavities 9 are located relative to one another in the mannerdescribed above in the context of the first exemplary embodiment.

In particular, here as well, the cavities 9 are circular rings that areself-contained in the circumferential direction; see FIG. 5.

This second exemplary embodiment is distinguished from the firstexemplary embodiment in that the cross section that the cavities hereeach have in a sectional plane that contains the axis of rotation isdesigned somewhat differently from that in the first exemplaryembodiment. While this cross section in the first exemplary embodimentwas ideally hexagonal, here the cavities have a predominantlyrectangular cross section, which is bounded by two rectilinear portionsthat each define the outer and inner circumference of the cavity, andtwo portions extending in concave fashion toward the interior of thecavity, which concave portions connect the two aforementionedrectilinear portions to one another. In particular, see FIG. 6. FIG. 6shows the cross section of an individual cavity of this exemplaryembodiment in an enlarged view.

It is especially advantageous if the cavities in the circumferentialdirection form a self-contained circular ring, in the way that has beendescribed above for the first exemplary embodiment. However, this is notabsolutely necessary. On the contrary, there may be applications inwhich it is especially favorable if the primary direction of thecavities extends on principle in the circumferential direction (which isthe case if the greatest length of the cavity is in the circumferentialdirection), but the individual cavities each form only circular-annularsegments, a plurality of which are located in alignment with one anotherin the circumferential direction; see for example FIG. 16, which will beaddressed again in further detail hereinafter. It is especiallyfavorable in this case if, viewed in the circumferential direction, atleast the three cavities shown in FIG. 16, and even better six suchcavities, are located in alignment with one another.

For other intended uses, it has proved especially advantageous if theprimary direction of the cavities (that is, their greatest length)extends parallel to the axis of rotation R. This embodiment can bereadily explained in conjunction with FIGS. 7 through 10.

In the exemplary embodiment shown in FIGS. 7 through 10, the main body 2and the tube part 3 have been created from the outset by being jointlyshaped by primary shaping, by means of the layer-melting process alreadymentioned. In the course of the primary shaping, as an integralcomponent of the tube part 3 and/or of the main body 2 (not shown here;more about this later), the cavities embodied therein are created.Alternatively, the procedure here can also be as has already beendescribed for the first exemplary embodiment—namely that the tube part3, including the cavities 9 located in it, is formed in one piece byprimary shaping, separately from the main body 2, which in turn isshaped by primary shaping independently of the tube part 3 and is joinedlater to the tube part 3.

The cavities that are used in this exemplary embodiment of FIGS. 7through 10 are distinguished in that their length in the directionparallel to the axis of rotation is greater by a factor of at least 5than their length in the circumferential direction. Preferably, each ofthese cavities, along the entire length of the tool receptacle 4 or atleast ⅔ of the length of the tool receptacle, has a continuouslyuninterrupted course. Here as well the large number of cavities isstriking; as the drawings show, more than 20 cavities are provided here.

The cavities 9 are in principle located relative to one another in theway already described above in detail in conjunction with the firstexemplary embodiment.

In this exemplary embodiment as well, the cavities are located on thesethree imaginary circular cylinders, which are each concentric with theaxis of rotation R and have different mean diameters R1, R2 and R3; seeFIG. 10. The cavities 9, each located on an imaginary circular cylinder,are located in alignment with one another in the circumferentialdirection; see FIG. 9. Those cavities 9 that are located on the secondimaginary circular cylinder, whose radius R2 is somewhat greater thanthe radius R1 of the first imaginary circular cylinder, are not alignedin the radial direction with the cavities that are located on the firstimaginary circular cylinder having the radius R1. Instead, they areoffset, preferably center-offset. This means that each cavity that islocated on the second imaginary circular cylinder is located, viewed inthe radial direction, in the interstice between two cavities 9 that areboth located on the first circular cylinder having the radius R1. Inthis exemplary embodiment, the cavities located on adjacent circularcylinders partly overlap as viewed in the circumferential direction; seeFIG. 9.

Preferably, those cavities 9 that are located on the third imaginarycircular cylinder, whose radius R3 is greater than the radii R1 and R2,are radially aligned with the cavities 9 of the first imaginary circularcylinder; again, see FIGS. 9 and 10.

With respect to this exemplary embodiment as well, it has provedespecially favorable if the individual cavities are small-celled, in thesense that the cross section of each individual cavity, in the planethat is perpendicular to the axis of rotation R, is smaller than 60 mm²,and ideally even smaller than 30 mm².

The set of cavities thus located has the damping effect alreadydescribed in detail above, which here as well is especially andunexpectedly strongly pronounced whenever the cavities are at leastpredominantly embodied as genuine enclaves, which are entirelyself-contained and have no connection whatever with the surroundings ofthe tube part.

Moreover, a set of cavities located in this way, as FIGS. 7 through 10show, also exhibits the insulating effect already addressed above, whichsimplifies the shrinking out.

However, the focus of action in this exemplary embodiment is shiftedsomewhat:

Even if in an individual case the dimensioning is critical, it can besaid as a rough rule of thumb that a set of cavities in which theprimary direction of the cavities is in the circumferential directionhas an especially pronounced damping effect and a tendency to a lesserinsulating effect, while in a set of cavities in which the whose primarydirection of the cavities is in the direction parallel to the axis ofrotation R, the tendency is the reverse. Such cavities have anespecially strong insulating effect and a tendency to a less-pronounceddamping effect.

FIGS. 11 through 14 show a further exemplary embodiment, which isclosely related to the exemplary embodiment of FIGS. 7 through 10, andwhat has been said in conjunction with FIGS. 7 through 10 appliesaccordingly, unless otherwise stated in the ensuing explanations.

In this exemplary embodiment, cavities 9 in a plane perpendicular to theaxis of rotation R are equipped with a hexagonal cross section, so thatadjacent cavities, or the lands dividing them, form a honeycombstructure.

A striking aspect of this exemplary embodiment is the markedly highnumber of cavities. There are more than 50 cavities. By far the majorityof them (for instance, in this exemplary embodiment shown in thedrawing, all of these cavities 9) are embodied as genuine enclaves.

FIGS. 15 through 18 show a further exemplary embodiment of theinvention.

This exemplary embodiment of the invention is distinguished in that themain body 2 and the tube part 3 have been created in one piece from theoutset by being jointly shaped by primary shaping. The entire toolholder has been constructed by means of a layer-melting process of thetype described above.

In this exemplary embodiment, the tool holder is provided with a numberof cavities 9, which correspond to the above-described second exemplaryembodiment, so that what is said for that embodiment applies to thecavities here as well. Alternatively, it is naturally also possible forcavities to be provided of the kind that illustrate the other exemplaryembodiments described above.

The special aspect of this tool holder is as follows:

The tool holder is provided with at least one coolant supply line 11, asFIG. 17 shows. For this kind of coolant supply line, which will bedescribed in further detail immediately hereafter, separate protectionis also claimed; that is, very generally, protection is claimed for atool holder produced with the aid of a layer shaping process; it has acoolant supply line 11 of the type described in further detail below,regardless of which features it also has otherwise.

This coolant supply line 11 extends from the face end of the tube part 3of the tool holder into the main body 2. There, it discharges at theinner circumferential surface of the main body. Preferably, this coolantsupply line 11 extends to beneath the retaining flange 6 for handling ofthe tool holder, which retaining flange is provided on the main body.

The special aspect of this coolant supply line 11 is that it does notpierce the tool holder in the radially outward direction, nor has itpierced it at any time.

This coolant supply line 11, for this purpose, preferably comprises atleast two and even better three different portions. In the concretecase, the coolant supply line 11 has a first portion 11.1 (FIG. 17),which extends in the radially outward direction, substantiallyperpendicular to the axis of rotation R, from the inner surface of themain body 2. The radially outward end of this portion 11.1 is adjoineddirectly by a second portion 11.2, which is preferably rectilinear andextends obliquely to the axis of rotation R from the main body 2 intothe tube part 3; see FIG. 17a . Immediately adjoining the end, locatedin the tube part 3, of this portion 11.2 is a third portion 11.3 of thecoolant supply line 11; it extends into the face end of the tube partand discharges there; again, see FIG. 17 a.

A T intersection, in the sense that a portion of the coolant supply line11 extending from the inside outward in the radial direction isintersected laterally along the way by a portion of the supply lineextending substantially parallel to the axis of rotation R, isunnecessary here. This makes rational production possible, because thenecessity of closing off branches of the coolant supply line 11 thatdischarge in the outer circumferential surface of the tool holder with astopper or the like can be dispensed with.

For the sake of completeness, it should be noted that the aforementionedsecond portion 11.2 and the aforementioned third portion 11.3 of thecoolant supply line 11 need not necessarily be different portions.Instead, they can fuse into a single portion, extending in a suitablycurved fashion, for instance a banana-shaped curved portion. Inlogically the same way, naturally, the first portion 11.1 and the twoother portions 11.2 and 11.3 can fuse together, for instance forming acoolant supply line that overall preferably extends steadily in J-shapedfashion (not shown in the drawings). The decisive factor is that anensemble of a plurality of bores, partly made from the outercircumference and needed only partly for the actual fluid line andotherwise forming a “dead side arm” can be dispensed with.

Although this is not shown in the drawings on its own, it may befavorable to lend the coolant supply line 11 a variable, that is,increasing or decreasing, inside cross section in the flow direction. Inthis way, a pressure drop, for instance, which otherwise occurs over thelength of the coolant supply line and interferes there, or which occursadjoining a branch of the coolant supply line in a plurality of limbsdischarging at different locations, can be compensated for.

A further embodiment option, which is easy to implement with the aid ofthe invention, is the nozzle-like embodiment of the mouth region. Forinstance, nozzles oriented radially or in the circumferential directioncan be provided. The term “nozzle” is preferably understood to mean alocal narrowing or a correspondingly acting deflection region of theflow cross section, which generates a fluid stream that emerges atincreased speed and therefore reliably and in a targeted way reaches theregion that is to be cooled and/or lubricated. In general, the dischargeregion can be designed largely freely with the aid of the invention.

A further advantage of this exemplary embodiment is that open grooves 13are machined into the surface of the tool receptacle 4 for receiving thetool; see in particular FIG. 17a . These grooves are preferably alreadyprovided in the course of the primary shaping of the tube part 3 or ofthe entire tool holder 1, so that in any case, the structure of the baseof the groove no longer changes later, even if the tool receptacle islater reamed or polished. The geometry of these grooves 13 can beselected relatively freely. The grooves 13 may be provided in order toexert additional influence on the hardness of the chucking of the toolshaft, or to exert further influence on what amount of heat istransmitted to the tool shaft in the course of the shrinking out again,within which period of time, by the tube part 3. The grooves canfurthermore, or alternatively, be provided in order to receive oilresidues and soiling that have been stripped off from the tool shaft forinstance as the tool shaft is inserted and which interfere with thechucking quality, unless they can be deposited in a region where theyare not a problem—but in these grooves, they are a problem.

Moreover, this exemplary embodiment is preferably distinguished in thaton the inner surface of the outlet 14, downstream of the tool receptacle4, one or in this case a plurality of positive-engagement elements areprovided, preferably in the form of the protrusions 15—this is an aspectfor which separate protection is also claimed; that is, very generally,protection is claimed for a tool holder produced at least partly withthe aid of a layer forming process, which has protrusions 15 of thiskind regardless of which features it otherwise also has. Thesepositive-engagement elements in the form of the protrusions 15 arepreferably embodied on the order of helical, inward-protruding ribs,so-called threaded ribs. The protrusion or protrusions 15 formpositive-engagement elements that engage corresponding grooves on thetool shaft and thus bring about a so-called “safelock functionality”,that is, protection against the tool shaft's being unintentionally beingpulled out in the direction of the axis of rotation R—as described byApplicant in its patent EP 2 004 351. What is decisive is that theseprotrusions 15 are an integral component of the tool holder and as arule have already been given their final shape by primary shaping in thecourse of the production of the tool holder. Advantageously, asmentioned, these protrusions are designed as a threaded rib, so thatthey have a length in the circumferential direction that is more thanmerely insignificant and as a result differ from the pin that isproposed in the aforementioned European patent.

FIGS. 19 through 22 show a further exemplary embodiment of theinvention. It is closely related to the exemplary embodiment describedabove in conjunction with FIGS. 15 through 18. What is said theretherefore applies to this exemplary embodiment as well, with thefollowing exceptions:

In this exemplary embodiment, the cavities are embodied in the wayalready described above for the second exemplary embodiment. That is,the cavities are predominantly and preferably all embodied as circularrings that are completely self-contained in the circumferentialdirection. A number of cavities 9 rests on each of at least twoimaginary cylinders of different diameters, in the way already describedabove. The decisive point now is that between radially successivecavities 9, at least locally so much space remains that at least one andpreferably a plurality of coolant supply lines 11 can be passed throughthe tube part in the direction substantially parallel to the axis ofrotation R, without intersecting the cavities 9; see FIG. 20. Preferablyhere again, at least three coolant supply lines 11 distributedsymmetrically over the circumference of the tube part are provided.

FIG. 22a and in particular FIG. 22b show a further important aspect ofthe invention, in the form of a special coolant damming chamber.Separate protection is also sought for it; that is, very generally,protection is claimed for a tool holder, produced at least partly withthe aid of a layer forming process, that has a coolant damming chamberas described in further detail below, regardless of what features itotherwise also has. In this exemplary embodiment, the coolant supplyline 11 does not have an open discharge site on the face end toward thetool by way of which the coolant exits uncontrolled into thesurroundings. Instead, on the face end of the tool holder 1 toward thetool, the coolant supply line 11 discharges into a coolant dammingchamber 22. The coolant damming chamber 22 is formed by a groove thatfunctionally divides a storage disk 23 from the tube part 3; however,the storage disk 23 is an integral component of the tube part 3 and isshaped together with it by primary shaping. The storage disk 23 coversthe mouth 24 of the coolant supply line 11 and deflects the flow ofcoolant by more than 60°. The storage disk 23 extends to nearly the toolshaft 25 and forms an annular gap 26 opposite it. This annular gap 26generates a high-speed coolant stream. The coolant stream is spunclosely along the tool shaft 25 and in this way reaches the tool cuttingedges, without fanning out substantially along the way, which wouldcause the stream to be partly lost for cooling the tool cutting edges.If necessary, a number of radially extending slits 27 are provided inthe storage disk 23, which additionally vary the shape of the coolantstream.

FIGS. 23 through 25 show a further exemplary embodiment of theinvention.

In the exemplary embodiment that these drawings show, no cavities 9 areprovided in the vicinity of the tube part 3. This need not necessarilybe the case, however; cavities can additionally be provided that areembodied as described above in the context of one of the exemplaryembodiments described above.

In the exemplary embodiment which these drawings show, it is moreoversuch that the main body 2 and the tube part 3 have been created in onepiece from the outset by being jointly shaped by primary shaping. Theentire tool holder has been constructed by a layer-melting process ofthe type described above. However, this too need not necessarily be thecase. Instead, it can certainly be that the main body 2 and the tubepart 3 are shaped by primary shaping separately from one another andonly joined together later. That too has already been described above.

The decisive point is that in this exemplary embodiment, the main body2, outside the tube part 3, has at least one cavity 9 and preferably aplurality of cavities 9, which each represent one complete enclave inthe main body 2. Ideally, these cavities 9 are provided in a region ofthe main body 2 that is embraced on its outer circumference by theretaining flange 6, which serves the purpose of automatic handling ofthe tool holder.

Precisely this region has been embodied in markedly massive fashion inthe tool holders known from the prior art. Surprisingly it has beenfound that precisely this region has a markedly high damping potential,if one or more cavities 9 are located in it.

It has proved to be highly expedient to provide these cavities each witha cross section the maximum length of which in the radial direction issubstantially greater than its maximum length in the direction parallelto the axis of rotation R; see FIG. 23. A n especially good outcomeensues if the maximum length of each cavity 9 in the radial direction isgreater by a factor of at least 3 and even better of at least 4 than themaximum length of the cavity 9 in the direction of the axis of rotationR.

If cavities are also provided in the tube part 3, then preferably thevolume of a single cavity 9 in the vicinity of the retaining flange issubstantially greater than that of the other cavities 9, and this volumeis preferably greater by a factor of at least 10 and even better of atleast 30 than the volume of a single cavity in the vicinity of the tubepart.

Ideally, each of these cavities 9 forms a circular-annular disk, whoseaxis is coaxial to the axis of rotation R. Preferably, at least two suchcavities 9 are provided. It is especially favorable if these cavities 9are substantially or completely aligned with one another in thedirection parallel to the axis of rotation R.

This kind of embodiment and positioning of the cavities 9 isparticularly important whenever the cavities 9 do not form an enclavebut instead communicate locally with a pressure transducer that can beactuated from outside.

An optional version of this kind is shown in FIG. 25. As can be seen,each of the cavities 9 here has a connecting line 16, which dischargesinto a threaded portion 17 that is accommodated in such a way that it isaccessible from outside, preferably in the vicinity of the retainingflange 6 for the handling of the tool holder. A stopper 18, typicallymeant to be actuated via a hexagonal socket, is made in the threadedportion 17, and the pressure in the applicable cavity 9 can be adjustedvia the depth to which the stopper is screwed in. Depending on how highthe pressure being exerted at the time is, the affected cavity 9 has amore or less pronounced damping behavior. The cavities 9 can bothcommunicate with one another and in that case are actuated by a singlepressure transducer, which is not shown in the drawings. Alternatively,naturally, an independent pressure transducer for each cavity can bepresent, as shown in FIG. 25.

FIGS. 25a and 25b show a further exemplary embodiment, which is highlysimilar to the exemplary embodiment just described and for which what issaid there applies accordingly, unless otherwise arising from thedifference described below.

In this exemplary embodiment, at least two cavities 9 are provided,which have the form of a cylindrical or conical ring. Preferably, thewall thickness of the respective ring in the radial directionperpendicular to the axis of rotation R is substantially smaller, and inthe ideal case by a factor of at least 3, than its length in thedirection parallel to the axis of rotation. Preferably, each of thecavities 9 is self-contained in the circumferential direction. It isespecially favorable if the cavities are located coaxially one insidethe other, so that an outer cavity 9 at least substantially completelyembraces an inner cavity 9.

A further exemplary embodiment of the invention is shown in FIGS. 26through 30. In this exemplary embodiment, the main body 2 and the tubepart 3 have been created in one piece from the outset by being jointlyshaped by primary shaping. Instead, however, a multi-part embodiment, asdescribed at the outset, is also readily possible.

A set of more than 20 or here even more than 30 cavities 9 is embodiedintegrally in the tube part and can be designed and located for instancesuch as has been described in the context of the second exemplaryembodiment. A different embodiment and a different location, forinstance as described in the context of the first exemplary embodiment,are also conceivable.

The decisive point in which the cavities used in the context of thisexemplary embodiment differ from the cavities described previously isthat the cavities 9, which are embodied in the one-piece tube part 3, inprecise terms do not form genuine enclaves. It is true that the cavities9 are closed substantially on all sides, however, adjacent cavities 9locally communicate with one another fluidly via connecting portions 19;see FIG. 28a . As seen from FIG. 28a , the connecting portions 19typically have an inside cross section in the flow direction that issmaller than the inside cross section of the cavities 9 themselves,preferably by factor of 3 and ideally by a factor of 4. This isfavorable since connecting portions 19 shaped in this way on the onehand ensure that the cavities all communicate with one another, so thattheir internal pressure can be controlled centrally, and on the other,they have such an intense throttling action that because of throttlinglosses, energy is drawn from the flow that develops under the influenceof the vibration to which the tool holder and its cavities 9 areexposed, and a damping effect thus ensues.

At least one of the cavities 9 can communicate via an outer connectingchannel 20 with the region outside the tube part; see FIGS. 28a and 26.

In this way, all the cavities form a network of cavities fluidlycommunicating with one another, which network can be subjected tointernal pressure as needed by applying a suitable pressure via theouter connecting channel 20. Aside from this outer connecting channel 20or these outer connecting channels 20, however, the cavities do notcommunicate with the outer environment or the interior of the tube part.With the aid of the network according to the invention, comprisingspatially distributed cavities, it is structurally possible,substantially more precisely than before, to “adjust” how and where thetool holder is deformed or stressed by the pressure exerted.

Via this pressure, influence can for instance be exerted on the dampingeffect of the set of cavities. The higher the internal pressure in thecavities 9, the less is the damping tendency and therefore the harderthe clamping of the tool shaft. The pressure transducer can be embodiedsuch as described in the context of the previous exemplaryembodiment—for instance, it can be a screw actuated via a hexagonalsocket and screwed into the connecting portion, equipped with a femalethread (not shown in the drawings), which by the depth to which it isscrewed in determines the pressure in the network comprising thecavities 9 communicating with one another.

Optionally, via this pressure, influence can also be exerted forinstance on the pressure available for chucking the tool between thetube part 3 and the tool shaft. In that case the cavities must bedimensioned and located in such a way that they generate pressure forcesexerted radially inward, when they are correspondingly put underinternal pressure. These pressure forces increase (or even in anindividual case replace) the pressure exerted by the shrink fitting.

Given a suitable location and embodiment of the cavities, a set ofcavities of the kind being discussed in the context of this exemplaryembodiment can also be used to facilitate the shrinking out or to enabledismantling the tool shaft. To achieve this, the cavities must belocated and embodied such that they have the tendency to widen theinterior of the tube part or to widen the tool receptacle when they areput under suitable internal pressure. This too is possibly very simply,especially wherever instead of a few cavities designed arbitrarily,there is a set of cavities of more than 20 cavities and preferably morethan 30 cavities, which are an integral component of the tool holderproduced in one piece or of the tube part produced in one piece of thetool holder, and which also ideally can be synchronously put underappropriate internal pressure via one or a few pressure transducers,because these cavities all communicate with one another.

FIG. 29 shows a further, very special exemplary embodiment of theinvention. In the exemplary embodiment shown here, it is again true thatthe main body 2 and the tube part 3 have been created in one piece fromthe outset by being shaped jointly by primary shaping. However, amulti-piece embodiment is also readily possible here, of the kinddescribed at the outset. Preferably, here as well, integral cavities 9are formed on the specification of one of the foregoing exemplaryembodiments, but in this variant of the invention cavities need notnecessarily be present.

The special aspect in this exemplary embodiment is that the outercircumference of the tube part has an induction portion, here shown inblack. The induction portion shown in black extends radially inward fromthe surface of the tube part preferably by 0.3 mm to 1.5 mm, and ideallyby at least 0.5 mm to a maximum of 1.5 mm. The induction portioncomprises a metal that is electrically and magnetically conductive andtherefore heats up rapidly under the influence of a magnetic alternatingfield. The induction portion is not for instance a tube that has beenattached later to the outside of the tube part 3 and secured there.Instead, the induction portion is an integral component of the tube partthat has been shaped together with it by primary shaping and therefore,because it intrinsically has the nature of an a priori one-piececonnection to the inner portion of the tube part, it exchanges heat bythermal conduction. The induction portion can be shorter, viewed in thedirection of the axis of rotation, than what is shown in FIG. 29, but itshould have at least substantially the same length in the direction ofthe longitudinal axis as the tool receptacle 4.

Preferably, at least the inner portion, that is, a portion locatedinside the induction portion, of the tube part that is marked bycross-hatching comprises a metal that has a higher thermal expansioncoefficient than the metal comprising the induction portion shown inblack. Often, at least, the metal used for this portion has noelectrical and/or magnetic conductivity, or only substantially lesselectrical and/or magnetic conductivity, than the material of theinduction portion. The advantage of such an internal portion is that theinternal portion expands very quickly and far as soon as heat issupplied to it, heat that was generated in the induction portion withthe aid of an induction coil.

In the context of a preferred embodiment, it is provided that theremainder of the tool holder in turn is joined a priori in one piece tothe induction portion and to the portion of the tube part located insidethe induction portion, but itself at least locally comprises a metalmaterial that again has different properties, for instance such that ina locally restricted way it can carburize or be nitrided, in order to beable to subject especially critical places in this way to case hardeningor nitriding—without thereby adversely affecting the tool properties ofthe induction portion, for instance.

FIGS. 32 through 35 show a further exemplary embodiment of theinvention.

In this exemplary embodiment, the tool holder is embodied as a colletchuck. It therefore comprises a main body 2 with a retaining flange 6.The retaining flange 6 is adjoined here by an attachment portion 8 ofthe main body 2. The attachment portion merges with a clamping portion3, which is formed by a tube part. The tube part has a tool receptacle4, which intermittently forms a conical seat 28 into which the actualcollet 30, forming a further component of the tool holder, can bepress-fitted with the aid of a cap nut 29 forming a further component ofthe tool receptacle. This press-fitting is done in a manner known per sesuch that as soon as the collet has been driven into its conical seat,the arms of the collet close in the radially inward direction andbetween them clamp the tool shaft by frictional engagement.

In this embodiment, both the main body 2 and the clamping portion 3 and(optionally) the cap nut 29 belonging to the tool holder preferably havecavities in the sense of the invention—in the manner shown for instancein FIG. 32. If necessary, also (or even only) the collet is equippedwith cavities of the invention, which then are embodied such that all ofthem, or at least the great majority, also form enclaves in the arms ofthe collet.

For all these cavities, what is said for the previous exemplaryembodiments accordingly. For instance, the cavities in the embodimentshown in FIG. 32 are designed as described for the cavities that thesecond exemplary embodiment of FIGS. 3 through 5 has. Alternatively,however, the cavities can also be embodied as described in conjunctionwith the first exemplary embodiment of FIG. 1, or as described inconjunction with one of the other exemplary embodiments.

A special aspect in this exemplary embodiment is that in addition to thetube part embodying the clamping portion 3, preferably the main bodyalso is equipped with ideally two kinds of cavities—namely (so-called“pore forming”) cavities that are preferably likewise embodied asdescribed in conjunction with one of the exemplary embodiments describedabove and especially expediently are embodied with additional cavities,which are larger and designed as described in conjunction with FIGS. 22athrough 25 b.

The cavities provided in the tube part that forms the clamping portion 3extend, viewed in the direction of the axis of rotation, preferably overthe entire length of the tube part and are ideally also provided in thevicinity radially below the thread for tightening the cap nut 29. Hereas well, the cavities ensure improved damping, as described above.

Moreover, here again, the cavities are preferably provided in such alarge number (in the vicinity of the portion between the main body 2 andthe tube part 3, for instance, at least 8 layers and in the drawing even10 layers of cavities are provided in the radial direction, located onimaginary circular cylinders located coaxially one inside the other)that for this tool holder as well, the result is a weight reduction thatimproves handling, for instance on the order of at least 10% better andeven at least 20% better in comparison to a corresponding tool holderthat comprises solid material throughout.

As already touched on, the cap nut 29 can also be provided with cavitiesof the variant embodiments already extensively described; these too areembodied as enclaves. It is expedient to provide them with cavities also(or only) on the portion that on its inner circumference forms thethread of the cap nut, which thread interacts with the counterpartthread on the tool holder. In this way, the cap nut becomes “softer” inthe radial direction without perceptibly losing clamping force in thedirection of the axis of rotation. Thus it does not act as a “stiff”belt that, where it forms the cone on its inside, nonresilientlyembraces the tube part and thereby excessively hinders the microscopicmotions of the tube part that are important for the damping and areintentionally enabled by the cavities in the clamping portion 3.

For the same reason, it can be expedient to equip the cap nut also (or,less preferably, only) with cavities of the invention where the portionof the cap nut 29 extending substantially in the direction of thelongitudinal axis merges with the radially extending portion of the capnut with which the cap nut acts directly on the collet; see FIG. 32.

Then it can be expedient for the collet 30 in turn to be equipped withcavities that form enclaves and that can be designed in accordance withthe variants that have already been described above. If such cavitiesare located in the arms of the collet that are separated from oneanother by slits, then naturally in the circumferential direction theydo not extend “through” but rather only so far in the circumferentialdirection as the applicable arm, so that they form an enclave withinthat arm.

In conclusion, a final exemplary embodiment is shown in FIGS. 36 through40.

In this exemplary embodiment, the tool holder is embodied as a cutterhead receptacle; in the drawings, tool receptacles that are for exampleequipped with a cutter head 33 are shown.

Therefore the tool holder comprises a main body 2 with a retainingflange 6. The retaining flange 6 is adjoined here also by an attachmentportion 8 of the main body 2. This attachment portion merges with theclamping portion 3, which is formed here by a tube part that on itsouter circumference forms a tool receptacle for a cutter head 33. Theinterior of the tube part here has a female thread, into which theretaining screw 31 can be screwed, which fixes the cutter head 33 in thedirection parallel to its axis of rotation. As best seen from FIGS. 38and 39, the main body 2 is additionally provided withpositive-engagement elements 32, here embodied as bolts press-fittedinto the main body, which have appropriate fitting faces and actionfaces, by way of which bolts the cutter head 33 is slaved in thecircumferential direction.

In this embodiment as well, the clamping portion 3 has cavities in thesense of the invention—in the way shown very clearly for instance inFIG. 39. Preferably, the main body 2 also, or even only the main body 2,has cavities.

For all these cavities, what is said for the previous exemplaryembodiments applies accordingly. The cavities, for instance in theembodiment shown in FIG. 38, are designed as described for the cavitiesthat the exemplary embodiment of FIGS. 3 through 5 has. Alternatively,the cavities can, however, also be embodied as has been described forthe first exemplary embodiment of FIG. 1, or as described for one of theother exemplary embodiments.

A special aspect in this exemplary embodiment is that in addition to thetube part that forms the clamping portion 3, preferably the main bodyalso is equipped with ideally two types of cavities, as has already beendescribed for the immediately preceding exemplary embodiment.

The cavities provided in the tube part forming the clamping portion 3extend, viewed in the direction of the axis of rotation, preferably overthe entire length of the clamping portion. Here as well, the cavitiesensure improved damping, as described above.

In addition it should be noted that for this kind of tool holder in theform of a cutter head receptacle, it can be especially favorable if theattachment portion 8 of the main body, which portion is located betweenthe retaining flange 6 and the clamping portion 3, is equipped with ahigh number of cavities (at least 25 and even better at least 50), sothat this region predominantly has a porous structure which contributesto a particular degree to the damping.

In general it should be said that the cavities are preferably providedin such a large number (in the vicinity of the portion between the mainbody 2 and the tube part 3, for instance, at least 8 layers and in thedrawing even 10 layers of cavities are provided in the radial direction,located on imaginary circular cylinders located coaxially one inside theother) that for this tool holder as well, the result is a weightreduction that improves handling, for instance on the order of at least10% better and even at least 20% better in comparison to a correspondingtool holder that comprises solid material throughout.

Following the exemplary embodiments, it should be said quite generallythat independently of and in addition to the claims presented thus far,protection is also claimed for collets per se that are equipped with thecavities of the invention. Expediently, these collets are designed, asdescribed above and not least also by the drawings, which show theclaimed collet in its intended environment. The cavities areadvantageously embodied as described above for the tool holders.

Following the description of the individual exemplary embodiments, itshould also be stated quite generally that in addition to andindependently of the claims presented thus far, independent patentprotection is also sought for a cap nut, which is equipped with anaction face for driving a collet into its conical seat and is providedwith a plurality of cavities, which each form an enclave in the cap nut,the cavities advantageously being embodied as described above for thetool holders.

In closing, it is noted quite generally that protection is also soughtfor a tool holder and method for producing such a tool holder, whichhave the features that are recited in one or more of the ensuingparagraphs.

This protection is claimed in each case in the sense that the featuresmay be present in addition to the features that are specified by one ormore of the appended claims. However, this protection is also claimed inthe sense that whenever “preferably of one of the claims” and/or“method”, this is a set of features that at an appropriate time issought as a basis for a further main claim, which is independent of thefeatures of the main claim pursued thus far.

When “foregoing paragraphs” are referred to, this is a reference to theparagraphs following this sentence.

A tool holder (1) for chucking of a tool shaft by frictional engagement,having a main body (2) for coupling the tool holder (1) to the spindleof a machine tool and having a clamping surface (3), joined to it, or atube part (3) joined to it, for fixation of a tool shaft by frictionalengagement, characterized in that the tool holder (1) has at least oneportion shaped in one piece by primary shaping, in which an outerconnecting channel (20) is embodied that extends into the interior ofthe portion and there widens, forming at least one cavity (9).

The tool holder (1), characterized in that the at least one cavity isfilled with a fluid, and a pressure producer, preferably to be actuatedfrom outside, is built into the at least one outer connecting channel(20), by means of which producer the fluid can he subjected to pressure.

The tool holder (1) of the foregoing paragraph and/or of one of theexisting claims, characterized in that that the cavities (9) form athree-dimensional set of cavities, which is distinguished in thatprogressively in the radial direction from the inside outward, aplurality of cavities (9) are located one after another, preferably inalignment with one another, and at the same time a plurality of cavitiesare located one after another in the direction of the axis of rotation(R), and preferably in alignment with one another.

The tool holder (1) of at least one of the foregoing paragraphs and/orone of the existing claims, characterized in that at least 10, and evenbetter at least 20, cavities (9) are present, which are preferably alllocated in the interior of the one-piece clamping surface or of theone-piece tube part (3), which communicate with one another via innerconnecting channels and which communicate via at least one outerconnecting channel (20) with a pressure producer that specifies thepressure of the fluid with which the cavities (9) are filled.

The tool holder (1) preferably of at least one of the foregoingparagraphs and/or preferably one of the existing claims, characterizedin that the tool holder (1) has at least one coolant supply line (11),which is machined into a region of the tool holder (1) comprising ametal layer material and extends into the main body (2) from the faceend of the tool holder (1) toward the tool to be chucked and preferablydischarges into the inner chamber bounded thereby, and the coolantsupply line (11) changes its directional course extension at least onelocation, without having a side arm that is formed by a bore that hasbeen made from the outer surface of the tool holder (1) into the toolholder (1).

The tool holder (1) of at least one of the foregoing paragraphs and/orone of the existing claims, characterized in that the coolant supplyline (11) has at least one portion that extends substantially in theradial direction.

The tool holder (1) preferably of at least one of the foregoingparagraphs and/or preferably of one of the existing claims,characterized in that the tool holder (1) in its interior has at leastone positive-engagement element, which is an integral component of aregion of the tool holder (1) comprising a metal layer material, andwhich positive-engagement element is designed such that bypositive-engagement interaction with the tool shaft that is firmlyretained substantially by positive engagement by the tool holder (1), itprevents the tool shaft from being unintentionally pulled out from thetool receptacle in the direction along the axis of rotation (R).

The tool holder (1) preferably of one of the foregoing claims,characterized in that the tool holder (1) has at least one coolantdamming chamber (22), which is bounded among other things by a dammingdisk (23), which is an integral component of a region of the tool holder(1) comprising a metal layer material, and the damming disk (23), viewedin the direction along the axis of rotation (R), preferably covers atleast one mouth site of at least one coolant supply line (11).

The tool holder (1) preferably of one of the foregoing claims, having amain body (2) for coupling the tool holder (1) to the spindle of amachine tool and a clamping surface (3), joined to it, for fixation andpreferably shrinking in of a tool shaft, in which a first portion of thetool holder (1) comprises forged or cast metal, characterized in that asecond portion of the tool holder (1) comprises a metal layer material,and the first portion is preferably the main body (2) of the tool holder(1), and the second portion is preferably the clamping surface (3) ofthe tool holder (1), or vice versa.

A method for producing a tool holder (1) having a main body (2) forcoupling the tool holder (1) to the spindle of a machine tool and havinga clamping surface (3), joined to it, for fixation and in particular forshrinking in of a tool shaft, in which a first portion, preferably themain body (2), is produced as a rotary part from the solid or from apre-forged or precast blank, preferably of tool steel, characterized inthat a second portion, preferably the clamping surface (3), which isideally embodied as a tube part, is constructed of individual metallayers that are generated successively on one another, until theclamping surface (3) has a predetermined shape.

The method as described, characterized in that the metal films formingthe first portion are melted from a mixture of different or differentlyalloyed metals.

The method as described, characterized in that the composition of themetal films is locally varied more than merely insubstantially, suchthat the metal films locally have special mechanical and/or electricaland/or magnetic properties.

The method as described, characterized in that the method is carried outfor producing the tool holder (1) in such a way that the clampingsurface (3), embodied in the form of a tube part, has an outer portionforming the outer circumference of the tube part, which outer portioncomprises a metal material in which heat can be generated inductivelyunder the influence of a magnetic alternating field, and which outerportion also has an inner portion, joined to it and made of the samematerial and forming the tool receptacle, and the inner portioncomprises a metal material that heats up less intensely, under theinfluence of an alternating field, than the material of the outerportion and at the same time has a higher thermal expansion than thematerial of the outer portion.

The method as described, characterized in that the second portion, afterthe conclusion of the generation of the individual layers, is subjectedto a preferably microstructure-changing heat treatment.

The method as described, characterized in that the first portion of thetool holder (1), which comprises forged or cast metal, is used as asubstrate, onto which the second portion of the tool holder (1), whichcomprises a metal layer material, is gradually applied.

The method as described, characterized in that the second portion or thetube part (3) s joined to the main body (2) and in particular weldedonly after the conclusion of the heat treatment.

The method as described, characterized in that the second portion or thetube part (3), after the conclusion of the generation of the individuallayers and preferably after the ensuing heat treatment, is subjected toa rotary machining and/or external and/or internal circular grinding,and the aforementioned machining ideally takes place only after thejoining of the main body to the tube part.

The method as described, characterized in that the tool receptacle,after the conclusion of the generation of the individual layers andpreferably after the ensuing heat treatment, is subjected to a reamingand/or grinding machining.

A tool holder (1) having a main body (2) for coupling the tool holder(1) to the spindle of a machine tool and having a tube part (3) joinedto it for thermal or hydraulic chucking of a tool shaft, characterizedin that the outer circumference of the tube part (3) has an inductionportion, which comprises a metal that is electrically and magneticallyconductive, and the portion located inside the induction portion of thetube part (3) comprises a metal which has a higher coefficient ofthermal expansion than the metal comprising the induction portion, andthe induction portion and the portion of the tube part (3) locatedinside the induction portion are both an integral, one-piece componentcircumferential wall of the tube part (3).

The tool holder as described, characterized in that the portion shapedin one piece by primary shaping comprises solely metal layers, zones orpoints, entirely without other components or at least without othercomponents that extend beyond the category of contaminants.

The tool holder as described, characterized in that the portion shapedin one piece by primary shaping entirely or partially comprises at leastone alloy, and in particular a shape memory alloy.

The tool holder as described, characterized in that the portion shapedin one piece by primary shaping is produced from at least one metalstarting material or a metal powder, which includes components of atleast one nonmetal material that affect the tool properties.

According to certain embodiments, the tool holder (1) has a main body(2), for coupling the tool holder (1) to the spindle of a machine tool,and a clamping surface (3) connected thereto for clamping a tool,characterized in that the tool holder (1) has at least one portionshaped in one piece by primary shaping, which in its interior has one ormore cavities (9) that form an enclave in the portion shaped by primaryshaping,

The tool holder may be characterized in that the clamping surface is atube part (3) for chucking of a tool shall in the tube part (3) byfrictional engagement.

The tool holder (1) may be characterized in that the cavities (9) in thecircumferential direction each form an annular-portionlike channel,which preferably extends concentrically to the axis of rotation (R) ofthe tool holder (1) entirely in the interior of the portion.

The tool holder (1) may be characterized in that the cavities (9) eachform an annular channel, which is completely self-contained in thecircumferential direction.

The tool holder (1) may be characterized in that the tool holder (1) hasa plurality of cavities (9), which extend substantially in the directionparallel to the axis of rotation (R) or along a helical line that windsaround the axis of rotation (R) and which are located preferablysymmetrically to one another in the circumferential direction.

The tool holder (1) may be characterized in that the cavities, in aplane perpendicular to the axis of rotation (R) or in a plane thatcompletely contains the axis of rotation (R), have a circular crosssection, a fiat cross section, or preferably a transverse sectioncomprising two lateral arcs concave toward the interior of the cavityand two straight lines, joining the arcs, or ideally a hexagonal crosssection.

The tool holder (1) may be characterized in that the tool holder (1) hasmore than 10 and preferably more than 15 cavities (9) that areindependent of one another and that are preferably all embodied entirelyin the portion that forms the clamping surface (3), and the clampingsurface is ideally embodied as a tubular portion.

The tool holder (1) may be characterized in that the cavities (9) form athree-dimensional set of cavities, which is distinguished in thatprogressively in the radial direction from the inside outward, aplurality of cavities (9) are located one after another, preferably inalignment with one another, and at the same time a plurality of cavitiesare located one after another in the direction of the axis of rotation(R), and preferably in alignment with one another.

The tool holder (1) may be characterized in that at least one andpreferably a plurality of cavities (9) are embodied in the main body(2), in a region located outside the clamping surface (3).

The tool holder (1) may be characterized in that the at least one cavity(9) is positioned such that in the radially inward direction it islocated entirely in a region which is embraced on its outercircumference by the retaining flange (6) for the handling system, forautomatic manipulation of the tool holder (1).

The tool holder (1) may be characterized in that the at least one cavity(9) has the form of an annular disk, whose axis of symmetry coincideswith the axis of rotation (R) and whose length in the direction parallelto the axis of rotation (R) is substantially less, preferably by atleast a factor of 3, than its length in the radial directionperpendicular to, the axis of rotation (R).

The tool holder (1) may be characterized in that the at least one cavity(9) has the form of a cylindrical ring, whose, wall thickness in theradial direction perpendicular the axis of rotation (R) is substantiallyless, and preferably at least by a factor of 3, than its length in thedirection parallel to the axis of rotation (R).

The tool holder (1) may be characterized in that a plurality of cavities(9) are located in the direction along the axis of rotation (R), or inthe direction along a straight line inclined by up to 10° relative tothe axis of rotation (R), in alignment with one another and as a resultare located on an imaginary cylindrical or conical jacket.

The tool holder (1) may be characterized in that a plurality of cavities(9) are located such that they are located on at least two, and evenbetter three, imaginary cylindrical or conical jackets located coaxiallyone inside the other.

The tool holder (1) may be characterized in that cavities (9) located ondifferent cylindrical or conical jackets are not aligned in the radialdirection but instead are preferably located with a center offsetrelative to one another.

The tool holder (1) may be characterized in that respective adjacentcavities (9) are located so close together that in a plane perpendicularto the axis of rotation they form a total cross section, whose totalarea is occupied by a maximum of 60%, and even better a maximum of 40%,of the sum of the cross-sectional area of the lands.

According to certain embodiments, the tool holder (1) has a main body(2) for coupling the tool holder (l) to the spindle of a machine tool,and a tube part (3) joined to it for thermal or hydraulic chucking of atool shaft, characterized in Mat the outer circumference of the tubepart (3) has an induction portion, which comprises a metal that iselectrically and magnetically conductive, and the portion located insidethe induction portion of the tube part (3) comprises a metal which has ahigher coefficient of thermal expansion than the metal comprising theinduction portion, and the induction portion and the portion of the tubepart (3) located inside the induction portion are both an integral,one-piece component of the circumferential wall of the tube part (3).

The invention claimed is:
 1. A tool holder for chucking a tool shaft byfrictional engagement, comprising: a main body for coupling the toolholder to a spindle of a machine tool; a clamping surface joined to themain body, or a tube part joined to the main body, for fixation of atool shaft by frictional engagement; and at least one portion of theclamping surface or tube part is shaped in one piece by primary shaping,in which an outer connecting channel extends into an interior of theportion and there, on a side of the clamping surface or tube part facingaway from a mouth of the tool holder, widens, forming a plurality ofinterconnected cavities with a first cavity connected directly to theouter connecting channel and connected to at least one second cavitypositioned in a direction toward an opening of the mouth of the toolholder, wherein the first cavity and each of the at least one secondcavities are connected to one another via a connecting channel having asmaller inside cross-section than an inside cross-section of the firstcavity and each of the at least one second cavities, and wherein theplurality of cavities are located entirely in the interior of theportion shaped in one piece by primary shaping, wherein the plurality ofcavities are tight on their own even at extremely high internalpressures since the plurality of cavities are embodied entirely insidethe one-piece portion, wherein the clamping surface or the tube part iscomposed of individual metal layers that are successively applied toeach other until the damping surface or the tube part has apredetermined shape, and wherein the plurality of cavities are filledwith a fluid, and a pressure producer, actuated from outside, is builtinto the at least one outer connecting channel, and the fluid can besubjected to pressure by the producer, and wherein the fluid flowsthrough the outer connecting channel into the first cavity withoutflowing in a countercurrent direction relative to the fluid flow throughthe first cavity.
 2. The tool holder of claim 1, comprising a pluralityof the at least one cavities, wherein the plurality of cavities form athree-dimensional set of cavities, which is distinguished in thatprogressively in a radial direction from inside outward, a plurality ofcavities are located one after another, in alignment with one another,and at the same time, in a direction of an axis of rotation, a pluralityof cavities are located one after another, and in alignment with oneanother.
 3. The tool holder of claim 1, wherein at least 10 cavities arepresent, which are all located in an interior of the one-piece clampingsurface or of the one-piece tube part, which communicate with oneanother via inner connecting channels and which communicate via at leastone outer connecting channel with a pressure producer that specifies thepressure of the fluid with which the cavities are filled.
 4. The toolholder of claim 1, wherein the tool holder has at least one coolantsupply line, which is machined into a region of the tool holdercomprising a metal layer material and extends into the main body from aface end of the tool holder toward the tool to be chucked, anddischarges into an inner chamber bounded thereby, and the at least onecoolant supply line changes its directional course extension at at leastone location, without having a side arm that is formed by a bore thathas been made from an outer surface of the tool holder into the toolholder.
 5. The tool holder of claim 4, wherein the at least one coolantsupply line has at least one portion that extends substantially in aradial direction.
 6. The tool holder of claim 1, wherein the tool holderin its interior has at least one positive-engagement element, which isan integral component of a region of the tool holder comprising a metallayer material, and which positive-engagement element is designed suchthat by positive-engagement interaction with the tool shaft that isfirmly retained substantially by positive engagement by the tool holder,the positive-engagement element prevents the tool shaft from beingunintentionally pulled out from a tool receptacle in a direction alongan axis of rotation.
 7. The tool holder of claim 1, wherein the toolholder has at least one coolant damming chamber, which is bounded amongother things by a storage disk, which is an integral component of aregion of the tool holder comprising a metal layer material, and thestorage disk, viewed in a direction along an axis of rotation, covers atleast one mouth of at least one coolant supply line.
 8. The tool holderof claim 1, wherein a first portion of the tool holder comprises forgedor cast metal, and a second portion of the tool holder comprises a metallayer material, and the first portion is the main body of the toolholder, and the second portion is the clamping surface or the tube partof the tool holder.
 9. A method for producing the tool holder of claim1, comprising: producing a first portion as a rotary part from a solidor from a pre-forged or precast blank of tool steel; and constructing asecond portion, which is a tube part, of individual metal layers thatare generated successively on one another, until the clamping surfacehas a predetermined shape.
 10. The method of claim 9, wherein the metallayers forming the second portion are melted from a mixture of differentor differently alloyed metals.
 11. The method of claim 9, wherein, thecomposition of the metal layers is locally varied more than merelyinsubstantially, such that the metal layers locally have specialmechanical and/or electrical and/or magnetic properties.
 12. The methodof claim 9, wherein the method is carried out for producing the toolholder in such a way that the clamping surface, embodied in the form ofa tube part, has an outer portion forming an outer circumference of thetube part, which outer portion comprises a metal material in which heatcan he generated inductively under an influence of a magneticalternating field, and which outer portion also has an inner portion,joined to the outer portion and made of the same material and formingthe tool receptacle, and the inner portion comprises a metal materialthat heats up less intensely, under an influence of an alternatingfield, than the material of the outer portion and at the same time has ahigher thermal expansion than the material of the outer portion.
 13. Themethod of claim 9, comprising subjecting the second portion, after theconclusion of the generation of the individual layers, to amicrostructure-changing heat treatment.
 14. The method of claim 9,comprising using the first portion of the tool holder, which comprisesforged or cast metal, as a substrate, onto which the second portion ofthe tool holder, which comprises a metal layer material, is graduallyapplied.
 15. The method of claim 9, comprising welding the secondportion or the tube part to the main body only after a conclusion of theheat treatment.
 16. The method of claim 15, comprising subjecting thesecond portion or the tube part, after a conclusion of the generation ofthe individual layers and after the ensuing heat treatment, to a rotarymachining and/or external and/or internal circular grinding, and theaforementioned machining takes place only after the welding of the mainbody to the tube part.
 17. The method of claim 16, comprising subjectingthe tool receptacle, after the conclusion of the generation of theindividual layers and after the ensuing heat treatment, to a reamingand/or grinding machining.
 18. The tool holder of claim 1, wherein theportion shaped in one piece by primary shaping comprises solely metallayers, zones or points, entirely without other components or at leastwithout other components that extend beyond a category of contaminants.19. The tool holder of claim 1, wherein the portion shaped in one pieceby primary shaping entirely or partially comprises at least one shapememory alloy.
 20. The tool holder of claim 1, wherein the portion shapedin one piece by primary shaping is produced from at least one metalstarting material or a metal powder, which includes components of atleast one nonmetal material that affect the tool properties.